Physiology of neurotransmitters

1. Physiology Of Neurotransmitters

2. Neuromodulators Helps transfer information in the form of nerve impulse Pre-synaptic to postsynaptic Neurohormones ?

3. Properties Of A Neurotransmitter Must be synthesized by a neuron Stored in pre- synatic endings Released at the synapse Has specific receptors on Post-synaptic membrane Suitable termination of action

4. Classification Group Ex’s Acetylcholine Ach Catecholamines NE, Epinephrine, Dopamine, Serotonin, Histamine Amino Acids Excitatory – Glutamate, Aspartate Inhibitory – GABA , Glycine Polypeptides ADH, oxytocin , endorphines , enkephalines , somatostatin , sunstance p , CRH, TRH..etc Purines Adenosine , ATP Gases NO , CO

5. Acetylcholine Distribution All preganglionic neurons Post- ganglionic parasymapthetic Neuromuscular junctions Many parts of brain Amacrine cells in retina

6. Receptors Nicotinic – ligand gated ion channel Two subtypes Muscarnic – G protein coupled Five subtypes (M1 to M5 )

7. Catecholamines Post ganglionic sympathetic nerves Adrenal medulla (NE)

8. Properties Adrenalin & Nor-Adrenalin Dopamine Receptors Alpha – 1, 2 Beta – 1, 2, 3 D1-5 Termination MAO COMT Same

9. GABA Major inhibitory neurotransmitter in brain and retina Produced by decarboxylation glutamate by glutamate decarboxylase

10. GABA a Brain Ligand gated ion channel GABA b Brain G protein coupled GABA c Retina Ligand gated ion channel

11. Actions Inhibitory neurotransmitter Site of action for Anaesthetics Sedatives ( benzodiazepins ) Alcohol

12. Glycine Predominantly inhibitory neurotransmitter Glutamate major excitatory neurotransmitter Derived from kreb cycle Termination – taken up by astrocytes Excitotoxic

13. Serotonin Aka 5 – Hydroxy tryptamine Found in CNS , ENS , retina In brain Raphe nucleus contain serotonin Derived from trptophan Receptors are 5HT 1-7 ( 7 types with subtypes ) Acts as a mood elevator Hallucinogen Also secreted by enterochromaffin cells ,platelets , basophills Smooth muscle contraction ,

14. Histamine Neurotransmitter and hormone Hypothalamus , limbic system H1, H2, H3 Smooth muscle contraction Secretion of HCL Increased capillary permeability

15. Substance P Its one of the major tachykinin (polypeptide11AA) Found in many parts of brain , GIT, Nerves NK 1 , 2, 3 are receptors

16. Functions Neurotransmitter for pain in dorsal horn of spinal cord in hypothalamus for endocrinal modulation Axon reflex Peristalsis in gut Along with dopamine in basal ganglia

17. Nitric acid Aka endothelium derived relaxing factor (EDRF) Blood vessels , brain Derived from arginine by NO synthase

18. Could it be ? 